Net View Command stopped working.....

Hi there,

the net view command has stopped working for machines outside of the server room vlan it has worked in this setup until a couple of days ago.  When you type net view you got nothing back as if its trying to find something and never returns, if you type net view //servername it works fine for that server.

Now if you take control of a server which is on another vlan and type net view it works perfectly.  I've restarted the wins server as I was told this could be the problem but I'm sure the problem may be a switch problem?  

Do you have any idears what could be coursing it?  Or any tests I can do? as I say apparently nothing has been changed on the network but for some unknown reason it just stopped working.

Any help most welcome :)